System and Method for Graph Encoding of Physical Activity Data

ABSTRACT

A method for determining properties associated with a graph is disclosed herein. The graph includes a plurality of nodes and a plurality of connections between the nodes. The method comprises receiving global positioning system (GPS) data points for a plurality of GPS tracks associated with the graph. The method further comprises mapping the GPS data points for each of the plurality of the GPS tracks to the graph by determining an activity track based on the GPS track, the activity track including a plurality of nodes from the graph and at least one connection between the nodes. Additionally, the method comprises creating a path matrix including a plurality of values, each value in the path matrix associated with (i) one of the plurality of connections between nodes of the graph and (ii) one of the determined activity tracks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/657947, filed Mar. 13, 2015, which claims priority from provisionalpatent application Ser. No. 61/953,541, filed Mar. 14, 2014, the entirecontents of which are incorporated herein by reference.

FIELD

This document relates to the field of activity tracking systems, andparticularly to the analysis of existing graphs and activity associatedwith such graphs.

BACKGROUND

Runners, cyclists and other athletes are increasingly using online toolsto track fitness. Some online tools provide routes so that an athletemay select a route and record his or her performance for the route. Insome cases, an individual athlete may define a route for personal use orfor sharing. This can allow the athlete to track performance gains orlosses over time for the same route.

Some athletes find it motivating to use the same route as others andcompare results. This can be a relatively straightforward task ifathletes explicitly select predefined routes for workouts (e.g., byindicating to an online tool that fitness data was collected on apreviously defined “Route 1”).

However, unless athletes associate their fitness data with definedroutes (e.g., by selecting the defined route for which fitness data iscollected) it can be difficult to map multiple athletes' GPS data ontoknown locations of routes, such as streets, paths or trails so thatfitness activity at various locations can be analyzed.

Accordingly, it would be advantageous to provide an activity trackingsystem that allows athletes associate their fitness data with definedroutes and maps GPS data from various activities onto known locations ofroutes, such as streets, paths or trails. It would also be advantageousif the activity tracking system were configured to analyze the collecteddata from the various activities and provide insight concerning use ofthe routes, including metrics on commonly used portions of the routesand metrics on usage of the route by various people groups such aswomen, men, runners, bikers, etc. It would be additionally advantageousif the activity tracking system were configured to analyze the collecteddata and automatically identify previously unknown sections orconnecting paths within the route.

SUMMARY

Embodiments disclosed herein describe a system for collecting GPS dataand mapping large amounts of GPS time-series tracks of user fitnessactivity onto known locations of routes, which can be streets, paths, ortrails. By encoding fitness activity as a series of paths along anetwork of nodes and edges (or connections) between nodes, the amount ofdata needed to represent each track can be greatly reduced, allowingquick and simpler computations. Furthermore, graph theory processes canbe applied to determine a variety of useful parameters for potentialpaths. Tracks between nodes can be analyzed to determine actual paths onthe routes and determine statistical information for the aggregate offitness paths. This allows the ability to perform computations onfitness data to obtain relevant information both for users of thefitness tracking service, but also for organizations that need to makespecific queries across particular demographics, and particularlocations.

In at least one embodiment, a set of GPS time series tracks is createdfrom individual users traversing various paths within a system oftrails. A graph representation of routes, consisting of nodes and edgesis created and the GPS time series data applied to the graph to create asparse matrix representation of the routes and edges traversed during anactivity. In some cases, suggestions of additional paths to ‘grow’ thegraph can be determined.

Storing GPS data in an accessible way can be cumbersome for a variety ofreasons. Values of latitude and longitude need to be stored with highamounts of precision to allow incremental metrics of speed to becomputed. Furthermore, it is typically produced by mobile phones andwatches at a rate of about 1Hz (once a second), which means that atypical half-hour run will produce 3600 (1800 for both latitude andlongitude) floating-point numbers of very high precision, often withadditional timestamps. Graph encoding may be used to encode the same runwith less than 30 timestamps (or other number depending on the activitytrack traversed by the user), each for crossing a particular edge. Thiscan leads to a 100× reduction in storage requirements in some cases.

In addition to reducing data, graph encoding also allows a large varietyof questions to be answered directly from a single construct. Asdescribed in further detail below, if this construct is a sparse matrix,where every row represents an enumerated edge over a graph of aparticular area (such as a city), and every column represents anactivity track over a period of time (such as a year), and every nonzeroelement is simply the sequence of edges, then any aggregate statisticsof either activities or route segments (represented by edges) can beperformed by single operations of matrix algebra.

With graph encoding, operations shown by Graph Theory may be used on anymetric generated by the fitness activity to produce optimized pathsbetween particular nodes. For example, a cyclist may use graph theoreticoperations to find the shortest route available to work, or a runner mayfind the most popular routes to run at night for safety reasons. Graphtheoretic operations, such as bounded relaxation, also allow incrementalimprovement of existing paths, allowing suggestions for existing routesto be improved in a variety of ways, such as the determination of newnodes and new edges between nodes.

In accordance with at least one exemplary embodiment of the disclosure,there is provided a method for determining properties associated with agraph. The method comprises receiving global positioning system (GPS)data points for a plurality of GPS tracks associated with the graph. Themethod further comprises mapping the GPS data points for each of theplurality of the GPS tracks to the graph by determining an activitytrack based on the GPS track, the activity track including a pluralityof nodes from the graph and at least one connection between the nodes.Additionally, the method comprises creating a path matrix including aplurality of values, each value in the path matrix associated with (i)one of the plurality of connections between nodes of the graph and (ii)one of the determined activity tracks.

Pursuant to another exemplary embodiment of the disclosure, there isprovided a method for identifying an edge of a graph associated withselected demographic data from a user database, and a non-transitorycomputer readable medium containing instructions for performing suchmethod. The method comprises defining the graph within a boundedpolygon, the graph including a plurality of nodes and a plurality ofconnections between the nodes. The method further comprises receivingglobal positioning system (GPS) data points for a plurality of GPStracks from a plurality of GPS-enabled devices, and mapping the GPS datapoints for each of the plurality of the GPS tracks to the graph bydetermining an activity track based on the GPS track, the activity trackincluding a plurality of nodes from the graph and at least oneconnection between the nodes. Additionally, the method comprisescreating a path matrix including a plurality of values, each value inthe path matrix associated with (i) one of the plurality of connectionsbetween nodes of the graph and (ii) one of the determined activitytracks. The method further comprises defining a user profile vectorbased at least in part on the selected demographic data in the userdatabase, multiplying the path matrix and the user profile vector toobtain a resulting vector, and determining at least one edge of thegraph associated with selected demographic based on the resultingvector.

The above described features and advantages, as well as others, willbecome more readily apparent to those of ordinary skill in the art byreference to the following detailed description and accompanyingdrawings. While it would be desirable to provide an activity trackingsystem that provides one or more of these or other advantageousfeatures, the teachings disclosed herein extend to those embodimentswhich fall within the scope of the appended claims, regardless ofwhether they accomplish one or more of the above-mentioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings accompanying and forming part of this specification areincluded to depict certain aspects of the disclosure. It should be notedthat the features illustrated in the drawings are not necessarily drawnto scale. A more complete understanding of the disclosure and theadvantages thereof may be acquired by referring to the followingdescription, taken in conjunction with the accompanying drawings inwhich like reference numbers indicate like features and wherein:

FIG. 1 is a diagram illustrating at least one embodiment of an activitytracking system;

FIG. 2 is a diagram illustrating an exemplary GPS track of a user of theactivity tracking system of FIG. 1, the GPS track mapped to a graphincluding a plurality of nodes;

FIG. 3 illustrates an exemplary embodiment of a path matrix defined bythe nodes of the graph of FIG. 2 and a number of activity tracks definedby GPS tracks;

FIG. 4 illustrates an exemplary embodiment of a suggestion box based ondata from an activity track not included in the path matrix of FIG. 3;

FIG. 5 illustrates an exemplary embodiment of an operation performed onthe path matrix of FIG. 3 to render an edge property vector;

FIG. 6 illustrates another exemplary embodiment of a GPS track of a userof the activity tracking system of FIG. 1, the GPS track mapped to agraph including a plurality of nodes;

FIG. 7 illustrates another exemplary embodiment of a path matrix usingthe nodes of the graph of FIG. 6 and a number of activity tracks;

FIG. 8 is a flow chart of one embodiment of a process of derivingadditional graph activity data from the path matrix and the suggestionbox; and

FIG. 9 illustrates an exemplary embodiment of a client device andenterprise computing environment for the activity tracking system ofFIG. 1.

DESCRIPTION Activity Tracking System

With reference now to FIG. 1, a diagrammatic representation of oneexemplary embodiment of an activity tracking system 200 is shown. Theactivity tracking system includes GPS-enabled devices 210 configured forreceiving GPS data from the Global Positioning System satellites,sensing and collecting activity data associated with user 205, andsending the GPS data and the collected sensor data to the server 230over network 220 (e.g., the Internet, cellular network, LAN or othernetwork). Examples of GPS-enabled devices 210 include devices configuredwith GPS receivers such as smartphones, GPS watches, etc. GPS data mayinclude, for example, timestamp, latitude, longitude, and elevationdata. Sensor data may include actual physiological or contextualreadings or estimates associated with various physical activities of theuser, and such sensor data may be collected or determined in real timeor on a regular basis. Examples of sensor data include heart rate,power, motion, movement, speed, range, acceleration data, etc. TheGPS-enabled devices 210 may also be configured to collect the sensordata and display or transmit the sensor data. The term “activity data”as used herein refers to one or both of GPS data and sensor data.

In one embodiment, activity tracking system 200 may comprise a computingdevice (i.e., one or more computing devices), such as a server 230(including a plurality of servers) configured to perform a plurality offunctions embodied in various subsystems including, but not limited to,network site 231, data collector 233, graphing system 234 and graphencoding system 236. Those skilled in the art will appreciate that theexample shown in FIG. 1 is non-limiting and that configuration ofactivity tracking system 200 may vary from implementation toimplementation.

With continued reference to FIG. 1, the GPS data may be received andstored by GPS-enabled devices 210 during an activity by a user (e.g.,walking, jogging, running, biking, etc.). This GPS data provides thegeographic information of the recorded activity (e.g., latitude andlongitude data). The user may optionally record other data, such as theuser's heart rate or power, at a varied sample rate (e.g., 1-100 Hz orother rate) depending on the activity type, and any additionalinformation (e.g., cadence, stride rate, etc.) as appropriate, dependingon the particular GPS-enabled device that is used.

When an activity is completed by the user, the user instructs the deviceto send the recorded activity data over network 220 to the server 230.This can be sent directly if the device (such as a smartphone) has thecapabilities. Otherwise, the device may be linked to a networkedcomputer in order to deliver data. In other embodiments, the data maydelivered real time or near real time using any of various networks.

The device 210 can provide this time series data for the activity,create a data file that is temporarily stored in memory, and send thedata file. An example of activity data is provided in table 1, below.The activity data for the activity may include GPS data and sensor data(e.g., altitude data, acceleration data, heart rate data, or any ofvarious other types of sensor data or other data).

TABLE 1 timestamp latitude longitude other (ex. heart rate) 1.043567−97.3453452345 35.234523456 150 2.2345 −97.3336362255 35.231213451 1513.2345452 −97.3336234534 35.193245234 150 4.234535 −97.343456012035.225234623 150

According to one embodiment of the activity tracking system 200,activity data may be forwarded to the server 230 over the network 220 bya mobile application that may identify a user associated with the GPSdata and an indicator that the activity data is associated with aworkout, a type of activity (e.g., running, cycling, rowing or otheractivity). Network site 231 can provide a site accessible over a networksuch as the Internet or other network with an interface, such as an API,REST interface, thick client interface or other interface to allowGPS-enabled devices 210 or other client devices to interact withactivity tracking system 200 to provide activity data and receiveinformation.

Data collector 233 is configured to store the received activity data ina data store 240 as activity data 241. Furthermore, activity trackingsystem 200 may maintain profile data 242 for users, such as demographicinformation. Profile data 242 may include, by way of example but notlimitation, age, gender, height, weight, preferences, performance level(e.g., beginner, intermediate, professional, etc.) or other information.Activity data 241 and profile data 242 may be stored such that GPStracks (i.e., traversals of a particular street or path network definedby time-series GPS data) are associated with workouts (e.g., by uniquework ids), users, dates and other information. Thus, data store 240 maystore a large amount of activity data associated with users andworkouts.

Constructing a Graph

With continued reference to FIG. 1, graphing system 234 is configured toconstruct a graph 244 from a set of coordinate data 243 (which may alsobe referred to herein as “map data”). According to one embodiment, mapdata 243 can be a set of latitude and longitude coordinates for streetswith coordinates appearing at each intersection. For example, U.S.census publishes a database of latitude and longitude sequences forevery street recorded, with nodes appearing at every intersection.(Topologically Integrated Geographic Encoding and Referencing filesavailable from United States Census Bureau). Graphing system 234 cananalyze the map data and build a network by assuming that overlappingstreets with nodes within a very small value (such as a meter or othervalue) represent an intersection, and mark each of these nodes with asingle unique value. Though this does not contain explicitdirectionality or connectivity between nodes (one-way streets,overpasses), this type of connectivity can be inferred from userbehavior, as explained in further detail below. Alternatively,OpenStreetMap.org (www.OpenStreetMap.org) regularly publishes morecomplete datasets with explicit connectivity. Map data 243 may alsoinclude files from other sources.

The graphing system 234 is configured to construct a graph from map data243 for any sized region as selected by an administrator. In some cases,separate graphs may be maintained for different regions of interests.For example, different cities may be represented in different graphs. Inanother embodiment, a single graph may be used for all regions.

A simplified example of a region with a street network 280 of interestfor which a graph is to be created is illustrated by the street networkof FIG. 2. As shown in FIG. 2, map data for a road system may includethe following data for a simplified example:

Main Street: Lat=y1, Lon=x1; Lat=y1, Lon=x2; Lat=y1, Lon=x3;

Stone Road: Lat=y2, Lon=x2; Lat=y2, Lon=x3; Lat=y2, Lon=x4;

West Ave: Lat=y2, Lon=x2; Lat=y1, Lon=x2

Other information may also be included such as altitude, etc. The datacan be mapped to a series of nodes and edges. The nodes are specificpoints on the map. The nodes are typically crossing points, but are notnecessarily crossing points on the map. The edges are connecting pathsor lines between the nodes.

In FIG. 2, the example street network can be described as a list oflabeled nodes (labeled 1-6), the positions of those nodes (a latitude,longitude coordinate for each node), and list of edges extending betweenthe nodes, with each edge represented as with an ordered pair of nodes:

G=(1,2), (2,3), (2,4), (4,5), (5,6)

where G is a graph describing the example street network of FIG. 2(i.e., the nodes and connections that define the route segments alongand between Main Street, West Ave., and Stone Road) as a list of orderedpairs of nodes. This list of ordered pairs assumes that graph G isundirected, so that ordered pairs (1,2) and (2,1) are redundant.However, some operations and/or metrics may use a directed graph (suchas elevation). Transforming graph objects between directed andundirected states is understood by those of ordinary skill in the art.

Mapping GPS Data to Graph G

After the graph G is created, multiple GPS data time-series can bemapped onto the graph G to show potential routes that have beentraversed over the represented street network. Each such route that hasbeen traversed by a user is defined by a time-series of GPS data and isreferred to herein as a “GPS track”. A GPS track may represent a routetaken by a user during a walk, run, biking workout, or other monitoredtraversal of the route. For every GPS data point for a GPS track 290, anetwork computing device (e.g., server 230) computes the nearest node,forming a list. To limit this search for computational efficiency, itmay be preferable to only use nodes inside a bounding box 295 formedfrom the minimums and maximums of the longitude and latitude of track290, respectively. For larger activities, it may be more computationallyefficient to form a bounded polygon made up from a simplified GPSsequence. For simplification, Ramer Douglas Puekcer algorithm or otheralgorithm known or developed in the art may be used to form the boundingbox. For forming the polygon from the points, the linestring.bufferfunction in the Shapely python library or other mechanism known ordeveloped in the art may be used.

According to one embodiment, in order to map a GPS track to the graph G,a list or sequence of nodes of equal length to the number of GPS pointsis formed. Each node on the list represents the node on the graph G thatthe user 205 was closest to at the time the GPS coordinates weredetermined by the GPS-enabled device 210. For example consider a usermoving from node 1 to node 2 of FIG. 2 wherein twenty GPS data pointsare collected as the user moves from node 1 to node 2. Theearlier-in-time GPS data will show that the user is closest to node 1,and therefore each of these GPS data points (i.e., latitude andlongitude coordinates) is associated with node 1. The later-in-time GPSdata will show that the user is closest to node 2, and therefore each ofthese GPS data points is associated with node 2. At some point as theuser moves in-between node 1 and node 2 a transition is made from theGPS data point being associated with node 1 to the GPS data point beingassociated with node 2. In the example where twenty GPS data points arecollected between node 1 and node 2, a data point near the eleventh GPSdata point may represent this transition from node 1 to node 2, assumingthe user is moving at a constant pace. Accordingly, the list of GPS datapoints as the user moves from node 1 to node 2 in this example would beas follows: 1111111111 1222222222 2.

When a user traverses across several nodes during a GPS track, the listof GPS nodes will be redundant because the closest node onlyoccasionally changes within the typical GPS data collection interval(e.g., 1 second). These redundant nodes can be advantageously removed.In particular, a series of the same node can be reduced to a singleinstance. For example, if GPS track 290 in FIG. 2 renders the node list1111112222 3333555554 4444455522 2221111, the node list can be reducedto (1,2,3,5,4,5,2,1).

After preparing the sequence of nodes (1,2,3,5,4,5,2,1) as explained inthe previous paragraph, the sequence of nodes can be transformed into toa list of edges (i.e., node pairs, each node pair representing atraversal from one node to the next. For example, the sequence of nodes(1,2,3,5,4,5,2,1) can be transformed into the following list of edges:

p=((1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1))

-   -   where p is the path (or list of edges) describing the activity        of the user on GPS track 290. A path p created from a GPS track        290 may also be referred to herein as an “activity track”.

Comparing the list of edges for GPS track 290 (i.e.,(1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1)) to the graph G of FIG. 2(i.e., G=(1,2), (2,3), (2,4), (4,5), (5,6)), it will be noted that twoedges in path p do not exist in graph G. In particular, the graph G doesnot show the (3,5) edge or the (5,2) edge. The reason for this may beone of two reasons: (i) an error occurred with the GPS data, or (ii)there is a new path between the nodes that has yet to be defined in thegraph G. For illustrative purposes, assume that edge (3,5) is a newtrail that has not yet been encoded, and that edge (5,2) is due to GPSerror. Methods for distinguishing these incongruences will be describedin further detail below.

As noted previously, GPS data can be associated with a specific workout,user, and other information. Similarly, the path p for a GPS track mayalso be associated with a specific workout, user, or other information.In some cases, a path may represent an aggregation of GPS tracks for auser for a period, say a week or a year, or a single workout.

Constructing the Path Matrix and Suggestion Box

As noted previously, mapping of time-series GPS data for GPS track 290onto the street network 280 of FIG. 2 produced a path two sets of data,including (i) the part of the path on graph G (which may be referred toherein as “identified” edges or connections), and (ii) parts of the pathnot on graph G that represent either potential new paths or GPS error(which may be referred to herein ad “unidentified” edges orconnections). In order to determine whether the unidentified edges noton graph G represent either potential new paths or GPS error, thesequence of nodes for the GPS track 290 are stored in a “path matrix”246 (which may also be referred to herein as “PM”) and suggestions fornew edges in the graph G are stored a “suggestion matrix” 248 (which mayalso be referred to herein as “suggestion box” or “SB”). As explained infurther detail below, the path matrix 246 and the suggestion box 248 maybe an undirected graph from which computations of aggregate activitydata can also be performed. As also explained in further detail below, anumber of queries can be answered using PM 246. A client computingdevice 250 can provide a set query criteria to 252 to the server 230 ofactivity tracking system 200, such as, what are the most popular routes(i.e., the most frequented routes) for users having certaindemographics. Graph encoding system 236 can filter PM 246 based on thecriteria. Edges that meet the criteria can be returned along withvarious metrics. In some cases, the edges can be mapped to visualrepresentation of a map with color coding to visually identifyparticular edges meeting various criteria (e.g., a portion of a roadcorresponding to a most popular edge indicated in green, etc.)

The Path Matrix

An exemplary embodiment of a path matrix (PM) is shown in FIG. 3. Thepath matrix 246 in FIG. 3 is associated with the graph G, and includesinformation from the GPS track 290 of FIG. 2. The path matrix 246 isgenerally an m x n matrix where the m rows represent edges over aparticular area of a graph, and n columns represent an activity track(for a certain day, a particular workout or other period). Accordingly,the rows are defined by edge 1 (1,2), edge 2 (2,3), edge 3 (2,4), edge4, (4,5), and edge 5 (5,6). Again, these are the possible edges known tothe system based on graph G. The columns are defined by some number ofactivity tracks. The example activity track discussed above (i.e.,p=((1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1))) is represented as thefirst column in the PM 246 as shown in FIG. 3. The number of times oneof the edges from the graph G was traversed during the activity track isrepresented in the associated row of the column. For example, foractivity track 1 in the path matrix of FIG. 3 (i.e.,p=((1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1))), edge 1 was traversedtwice (i.e., p included (1,2) and (2,1)), edge 2 was traversed once(i.e., (2, 3)), edge 3 was not traversed, edge 4 was traversed twice(i.e., (1,2) and (2,1)), and edge 5 was not traversed. Note that both(1,2) and (2,1) in the path can be aggregated in a score of “2” sincethis edge (i.e., edge 4) was traversed twice in the same activity. Inanother embodiment, path matrix 246 may be applied to a directed graphsuch that there would be an entry for edge (1,2) and an entry for (2,1)in the first column. A number of additional activity tracks are alsoincluded in the path matrix, with one activity track represented in eachcolumn.

The Suggestion Box

An exemplary embodiment of a suggestion box (SB) is shown in FIG. 4. Thesuggestion box 248 generally includes a set of m×m sparse matrices, eachone representing the ‘suggestions’ of a potential connection for graph Gfrom an existing activity. Each sparse matrices includes an equal numberof rows and columns (i.e., m×m), where the number is equal to the numberof nodes in the graph. Therefore, for the graph G of FIG. 2 with sixnodes, suggestion box 248 is a 6×6 matrix.

With continued reference to FIG. 4, suggestion box 248 includes two dataentries, one for node combination (5,2) and another for node combination(3,5). These two node combinations represent both of the unknown edges(i.e., edges not currently included in the graph G) from the GPS track290 of FIG. 2. Accordingly, each of these unknown edges is a“suggestion” in the suggestion box 248. Suggestion (5, 2) is representedby a “1”,and suggestion (3, 5) is also represented by a “1” in thesuggestion box 248 of FIG. 4. These “suggestions” are in the suggestionbox 248 are for additional edges that could be added to the graph G,based on data collected from activity track 1. Additional data entriesmay be made to the suggestion box 248 based on other activity tracks(e.g., activity tracks 2 and 3 in the path matrix 246).

Since the path matrix 246 is, in some embodiments, an undirected graph,the matrices with suggestion box 248 can be sparse, and, by convention,upper triangular. This means that all suggested edges can be encodedwith an increasing row-column format.

-   -   Operations on the Path Matrix

Mathematical operations may be performed on the PM in order to determineat least one property for the graph G. Quick sparse computations can beperformed to create a variety of aggregate information. There are manycombinations of operations that can be performed, including, but notlimited to, the exemplary operations discussed in the followingparagraphs, with reference to FIG. 5.

A summary of all activity within the graph G can be obtained by theinner product PM*v, where v is a vector where each element is one (i.e.,vector v is a v×1 matrix). The vector v is of length n, which is equalto the number of activity paths in the path matrix 246 (i.e., the numberof columns in PM 246). Accordingly, because v=n the PM may be multipliedby the vector v. This operation of linear algebra produces a sum acrossall columns, producing a vector of length m (number of edges). Thisoperation may be used to obtain summary information from the path matrixon only a subset of activities. In particular, the operation can beperformed with a vector where only the elements representing the desiredactivities have a “1”.

By multiply the PM (m×n matrix) by a vector v, custom edges propertiesmay be created, representing aggregate data of any of various types. Toillustrate an example, consider the path matrix (PM) 500 in FIG. 5created by applying three paths to a graph, each path corresponding to adifferent workout. PM 500 has 3 edges (i.e., e₁, e₂, and e₃, which arenode combinations) and 3 workouts (w₁, w₂, and w₃, which are threeactivity tracks). Each workout was performed by one of three differentpeople having profile data 502. To determine the edge that is mostpopular with women, we multiply the PM 500 by the vector 504 (i.e.,vector (0,1,1)). The first row of vector 504 is negative and therefore a“0” because, as shown in profile data 502, the person who performedworkout w₁ is a male; rows two and three of vector 504 are positive andtherefore a “1” because workouts w₂ and w₃ were performed by females.When PM 500 is multiplied by vector 504, the result is another vector ofedge properties 506 (i.e., ep=(1,2,1)) as shown in FIG. 5. The highestvalue of vector 506 is found in row two, making the second edge e₂ themost popular edge.

Based on the foregoing example, it can be seen that creating a vector504 based on information in the profile data, and then multiplying thepath matrix 500 by that vector, results in a vector with edge propertiesthat is capable of identifying most used and least used edges by thedemographic represented by the user profile vector 504. As anotherexample, if one wanted to find the relative popularity of the edges withonly cyclists, PM 500 of FIG. 5 could be multiplied by vector (1,0,1)(which represents the cycling workouts in the example of FIG. 5).

In addition to determining most and least popular edges for a group ofactivity tracks, the multiplication operation on the path matrix mayalso be used to provide summary information about which activity tracksutilized a particular edge or group of edges. In particular, summaryinformation about a particular edge, or group of edges can be obtainedby the operation PM×v where v is a vector of length n made up of 1 s forthe desired edges. For example, to find all the workouts of e₂ in FIG.5, multiply PM by (0,1,0), which would give the vector ep (0,1,1). Thisvector ep (0,1,1) shows that only the 2nd and 3rd workout traversed edgee₂.

Combinations of the above operations using various vectors, along with adatabase of activities with useful attributes, can lead to a largevariety of useful information, such as age and gender profile forparticular streets, graphs of when particular members activitiesoverlap, etc.

Growing Graph G from the SB

As discussed previously, the suggestion box contains suggestions foradditional edges (i.e., unidentified edges) for graph G from eachactivity track in the set (i.e., in the path matrix). One embodiment ofgrowing graph G from these suggestions can include the steps describedbelow.

A first step for growing graph G is to sum the sparse matrices of thesuggestion box. Most sparse matrix libraries allow this operation to beperformed directly, producing a single sparse matrix with each elementrepresenting the total suggestions for a particular edge over allactivities on graph G. In other words, if multiple suggestion boxesexist for a given graph G, the summation of all the suggestion boxes forthe graph G will provide a total number of suggestions for each edge.

After the suggestion boxes are summed for a particular graph G, athreshold value may be used to determine which values in the suggestionbox represent GPS error, and which values in the suggestion boxrepresent legitimate trails that should be added to the graph G. Inparticular if a value in the suggestion box is below the thresholdvalue, it can be assumed that this suggestion is invalid and the resultof GPS error, or alternatively, the trail offered by the suggestion isnot sufficiently well-used to be included on in the graph G. On theother hand, if the value in the suggestion box is above the thresholdvalue, it can be assumed that this suggestion is valid and represents anew trail which should be represented by an edge on the graph G.

In at least one embodiment, a simple threshold value can be approximatedby some lower percentile (e.g., a value in the lower 5% to 15%, such as10%) of frequency of edge traverses from the existing edges in G. Forexample, if an edge in a particular path matrix has a value of “5”, andthis value places the edge in the bottom ten percent of all values inthe path matrix, a value of “5” may be a good threshold value.Alternatively, in another embodiment, past experience with othersuggestion boxes may indicate that a threshold value of “7” is a goodthreshold value. As noted previously, suggested edges that are above thethreshold, can be added as rows in the path matrix and graph G.Retroactively, is can be added to the columns of the path matrix for theactivities that produced the suggestions in the SB. For example, if edge(3,5) is added to the PM of FIG. 3, a count can be added to the PM foractivity track 1, which was derived from GPS track 290 of FIG. 2.

The method described above is useful in developing additional edges forgraphs. Various additional processing may be performed on the data toensure that the additional edges are accurate and useful. For example,in some embodiments, an edge will only be added if the nodes areseparated by a relatively short distance (say, less than 200 meters orother configurable distance). Additionally, some embodiments can verifythat the time taken to traverse each node is relatively consistent(e.g., within a configurable threshold deviation) before the edge isadded.

In some embodiments, additional values (heart rate, speed, elapsed time)can be encoded for nodes in the user's path. According to oneembodiment, the value for a parameter corresponding to the nearest GPSpoint in an activity track that is mapped to a node can be recorded. Forexample, for the sequence (1,2,3,5,4,5,2,1) discussed above, there mayhave been 100 GPS points in track 290 that map to node 3. Picking thetimestamp of the closest GPS point gives the time that the user wasclosest to the node. Similarly, the heart rate measurement taken closestto a node or timestamp could also be encoded for the sequence. Inanother embodiment, the values of a parameter corresponding to multipleGPS points can be averaged or otherwise considered. Using the exampleabove, if there are 100 GPS points that map to node 3, then 2-100corresponding heart rate values can be averaged for node 3.

For values that are cumulative (such as number of steps) it may bedesirable to perform the same operation and then compute the differencebetween the current and previous node to get an elapsed value for anedge (e.g., number of steps to traverse an edge).

One feature of cumulative data, such as timestamps, is that recordingsuch data implicitly encodes the order of the edges. Since thetimestamps are monotonically increasing, the next edge can be determinedby finding the next larger timestamp.

Cumulative data may be encoded in a directed graph form. Runners andcyclists often traverse the same street from different directions (suchas leaving and returning to their house). A directed graph will allowthese numbers to be distinct. For example, in the pathp=((1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1)), suppose it took theperson (6,7,8,9,6,7,7,6) seconds for each of the edges in the path,respectively. A directed graph would require a PM with twice the numberof rows of PM 246 of FIG. 3. To make cumulative timestamps, the sequence(6,13,21,30,36,43,50,56) can be calculated. The values for (3,5) and(5,2) can similarly be put into the suggestion box. If (3,5) passes thethreshold to be included within graph G, then the associated timestampcan also be inserted.

Loops in Paths

FIG. 6 is a diagrammatic representation of a GPS track 602 in which theuser made a loop. As discussed previously, the path for the GPS trackcan be represented as an activity track defined asp=((1,2),(2,3),(3,5),(5,4),(4,2),(2,3),(3,5),(5,6)). As shown in FIG. 6,the loop in the activity track occurred along edges (2,3), (3,5), (5,4),(4,2), (2,3) and (3,5). In some embodiments, it may be desirable toseparately record the case of multiple loops over a sequence of edgesduring a single activity. In some cases, the user may indicate that theymade one or more loops (e.g., by interfacing with his or her mobiledevice to mark the start of a new loop during a fitness activity orotherwise). In other cases, loops may be detected based on repeatingsequences of nodes.

FIG. 7 is a diagrammatic representation of one embodiment of a PM 700including entries for GPS track 602. In the embodiment FIG. 7, PM 700 isencoded with elapsed time to cross each edge. A column can be added foreach loop. In this example, PM 700 includes two columns for GPS track602. Additional suggestion box entries can also be created (e.g., asrepresented by 702 for the first cycle and 704 for the second cycle). Inthis example, each loop is essentially treated as a separate workout. Anadditional index can be added for the same workout for each loop.

Method of Expanding and Determining Properties of Graph

FIG. 8 is a flow chart illustrating one embodiment of a method ofexpanding a graph and determining properties for the graph, such asdetermining fitness data associated with the graph. As shown in FIG. 8,the method begins with step 802, wherein a graph G is constructed usingdata from various GPS tracks. The graph G may be constructed in themanner described above using graphing system 234 which is configured toconstruct the graph 244 in a database from a set of coordinate data 243.As described above, the graph includes by a plurality of nodes and aplurality of connections between the nodes. An exemplary graph is graphG=(1,2), (2,3), (2,4), (4,5), (5,6), which represents the street network280 of FIG. 2.

After the graph is constructed, the method continues with step 804wherein GPS data points are received for a GPS track associated with thegraph. The GPS data points may be transmitted from a GPS-enabled device(e.g., device 201 of FIG. 2) as a user traverses a route, and receivedin real time at a network computing device (e.g., server 230 of FIG. 2).Alternatively, the GPS data points may recorded by the GPS-enableddevice and uploaded to the network computing device after the usertraverses the route. In at least one embodiment, the GPS data points areassociated with additional information such as timestamps and fitnessinformation (e.g., heart rate, etc.) associated with the user along theGPS track.

After the GPS data points for the GPS track are received by the networkcomputing device (e.g., server 230), the method continues with step 806wherein GPS data points are mapped to the graph. This mapping processincludes determining an activity track based on the GPS track, theactivity track including a plurality of nodes from the graph and atleast one edge between the nodes. An exemplary activity track wasdescribed previously as the following list of edges:

-   -   p=((1,2),(2,3),(3,5),(5,4),(4,5),(5,2),(2,1)).

Next, the method continues with step 808 and the network computingdevice constructs a path matrix (e.g., PM 246 of FIG. 3) and asuggestion box (e.g., SB 248 of FIG. 4). The path matrix includes aplurality of values, and each value of the path matrix is associatedwith (i) one of the plurality of edges between nodes of the graph (e.g.,edges 1-5 of FIG. 3) and (ii) one of a plurality of activity tracks(e.g., activities 1-3 of FIG. 3). Any edges from an activity track thatare not associated with one of the plurality of edges of the graph are“unidentified” edges which are placed in the suggestion box. Asdiscussed previously, the suggestion box may include a matrixidentifying each of the possible connections in the graph and providinga value for any unidentified edges that occur in one or more of theactivity tracks.

The path matrix and the suggestion box may be used to determineproperties of the graph by performing operations on the graph, as notedin step 810 of FIG. 8, and may also be used to expand the graph based onthe unidentified edges, as noted in step 812 of FIG. 8. With referenceto step 810, a mathematical operation may be performed on the pathmatrix in order to determine at least one property for the graph. Forexample, as described above with reference to FIG. 5, if the path matrixis multiplied by a first vector derived from a user profile database, asecond vector will result that provides information on the most popularroutes for the user demographic defined by the first vector.

As noted previously in step 808, the suggestion box includesunidentified edges that were determined from one or more activitytracks. In step 812, a determination is made whether the unidentifiedconnection should be included in the graph. In at least one embodimentas discussed above, this determination may be based on a comparison ofthe value in the suggestion box to a threshold value. If it isdetermined that the unidentified connection should be included as aconnection in the graph, the graph is expanded, grown or otherwiseamended to include the unidentified connection.

Network Computing Environment

FIG. 9 is a diagrammatic representation of one embodiment of a networkcomputing environment 300 that may be used to implement the activitytracking system 200. For purposes of clarity, a single client computer,a single server computer, and a single data source are shown in thefigure. The client and server computers and data source represent anexemplary hardware configuration of data processing systems that arecapable of bi-directionally communicating with each other over a publicnetwork such as the Internet. Those skilled in the art will appreciatethat network computing environment 300 may comprise multiple servercomputers, and multiple client computers and data sources may bebi-directionally coupled to enterprise computing environment 330 overnetwork 320.

Client computer 310 is a GPS-enabled device, such as GPS-enabled device210 described previously with reference to FIG. 1. The client computer310 can include central processing unit (“CPU”) 311, read-only memory(“ROM”) 313, random access memory (“RAM”) 315, (“HD”) or storage memory317, and input/output device(s) (“I/O”) 319. I/O 319 can include akeyboard, monitor, printer, and/or electronic pointing device. Exampleof I/O 319 may include mouse, trackball, stylist, or the like. Clientcomputer 310 can include a cellular phone, a smart phone, a GPS phone,or any device capable of geotagging and communicating over a network.

Server computer 340 may have similar hardware components including CPU341, ROM 343, RAM 345, hard drive 347, and I/O 349. Data source 360 maybe a server computer having hardware components similar to those ofclient computer 310 and server computer 340, or it may be a data storagedevice. Server computer 340 may provide one embodiment of an activitytracking system.

Each computer 310 and 340 shown in FIG. 9 is an example of a dataprocessing system. ROM 313 and 343, RAM 315 and 345, storage memory 317and 347, and database 350 can include media that can be read by CPU 311and/or 341. Therefore, these types of computer memories includecomputer-readable storage media. These memories may be internal orexternal to computers 310 and/or 340.

Portions of the methods described herein may be implemented in suitablesoftware code that may reside within ROM 343, RAM 345, hard drive 347,database 350, data source 360 or a combination thereof. In someembodiments, computer instructions implementing an embodiment disclosedherein may be stored on a direct access storage device (DASD) array,magnetic tape, floppy diskette, optical storage device, or otherappropriate computer-readable storage medium or storage device. Acomputer program product implementing an embodiment disclosed herein maytherefore comprise one or more computer-readable storage media storingcomputer instructions translatable by CPU 341 to perform an embodimentof a method disclosed herein.

In an illustrative embodiment, the computer instructions may be lines ofcompiled C++, Java, or other language code. Other architectures may beused. For example, the functions of server computer 340 may bedistributed and performed by multiple computers in enterprise computingenvironment 330 or in a cloud in network computing environment 300.Accordingly, each of the computer-readable storage media storingcomputer instructions implementing an embodiment disclosed herein mayreside on or accessible by one or more computers in enterprise computingenvironment 330 or in a cloud in network computing environment 300.

Routines, methods, steps, operations or portions thereof describedherein can be implemented through control logic, including computerexecutable instructions stored on a computer readable medium, hardware,firmware or a combination thereof. The control logic can be adapted todirect an information processing device to perform a set of stepsdisclosed in the various embodiments. Some embodiments may beimplemented by using software programming or code in one or more digitalcomputers, by using application specific integrated circuits,programmable logic devices, field programmable gate arrays, optical,chemical, biological, quantum or nanoengineered systems, components andmechanisms. Based on the disclosure and teachings provided herein, aperson of ordinary skill in the art will appreciate other ways and/ormethods to implement the invention.

Computer executable instructions or code can be stored in acomputer-readable medium and can be operated on by a processor to permita computer to perform functions, steps, operations, methods, routines,operations or portions thereof described herein. Any suitable languagecan be used including C, C++, Java, JavaScript, assembly language orother programming or scripting code. Different programming techniquescan be employed such as procedural or object oriented. In an embodiment,HTML may utilize JavaScript to provide a means of automation andcalculation through coding.

Any particular step, operation, method, routine, operation or portionthereof can execute on a single computer processing device or multiplecomputer processing devices, a single computer processor or multiplecomputer processors. Data may be stored in a single storage medium ordistributed through multiple storage mediums, and may reside in a singledatabase or multiple databases (or other data storage). The sequence ofoperations described herein can be interrupted, suspended, or otherwisecontrolled by another process, such as an operating system, kernel, etc.The routines can operate in an operating system environment or asstand-alone routines.

A “computer-readable medium” may be any type of data storage medium thatcan store computer instructions, including, but not limited to read-onlymemory (ROM), random access memory (RAM), hard disks (HD), datacartridges, data backup magnetic tapes, floppy diskettes, flash memory,optical data storage, CD-ROMs, or the like. The computer readable mediumcan be, by way of example, only but not by limitation, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, system, device, or computer memory. The computer readablemedium may include multiple computer readable media storing computerexecutable instructions, such as in a distributed system or instructionsstored across an array.

A “processor” includes any hardware system, hardware mechanism orhardware component that processes data, signals or other information. Aprocessor can include a system with a central processing unit, multipleprocessing units, dedicated circuitry for achieving functionality, orother systems. Processing need not be limited to a geographic location,or have temporal limitations. For example, a processor can perform itsfunctions in “real-time,” “offline,” in a “batch mode,” etc. Portions ofprocessing can be performed at different times and at differentlocations, by different (or the same) processing systems.

It will be understood for purposes of this disclosure that a service ormodule is one or more computer devices, configured (e.g., by a computerprocess or hardware) to perform one or more functions. A service maypresent one or more interfaces which can be utilized to access thesefunctions. Such interfaces include APIs, interfaces presented for a webservices, web pages, remote procedure calls, remote method invocation,etc.

Embodiments can be implemented in a computer communicatively coupled toa network (for example, the Internet, an intranet, an internet, a WAN, aLAN, a SAN, etc.), another computer, or in a standalone computer. As isknown to those skilled in the art, the computer can include a centralprocessing unit (“CPU”) or processor, memory (e.g., primary or secondarymemory such as RAM, ROM, HD or other computer readable medium for thepersistent or temporary storage of instructions and data) and one ormore input/output (“I/O”) device(s). The I/O devices can include akeyboard, monitor, printer, electronic pointing device (for example,mouse, trackball, stylus, etc.), touch screen or the like. Inembodiments, the computer has access to at least one database on thesame hardware or over the network.

Steps, operations, methods, routines or portions thereof of the presentinvention may be implemented on one computer or shared among two or morecomputers. In one embodiment, the functions of the present invention maybe distributed in the network. Communications between computersimplementing embodiments of the invention can be accomplished using anyelectronic, optical, radio frequency signals, or other suitable methodsand tools of communication in compliance with network and othercommunications protocols.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, article, orapparatus.

Further, unless expressly stated to the contrary, “or” refers to aninclusive or and not to an exclusive or. That is, the term “or” as usedherein is generally intended to mean “and/or” unless otherwiseindicated. For example, a condition A or B is satisfied by any one ofthe following: A is true (or present) and B is false (or not present), Ais false (or not present) and B is true (or present), and both A and Bare true (or present).

As used herein, a term preceded by “a” or “an” (and “the” whenantecedent basis is “a” or “an”) includes both singular and plural ofsuch term unless the context clearly dictates otherwise. Also, as usedin the description herein, the meaning of “in” includes “in” and “on”unless the context clearly dictates otherwise.

Additionally, any examples or illustrations given herein are not to beregarded in any way as restrictions on, limits to, or expressdefinitions of, any term or terms with which they are utilized. Instead,these examples or illustrations are to be regarded as being describedwith respect to one particular embodiment and as illustrative only.Those of ordinary skill in the art will appreciate that any term orterms with which these examples or illustrations are utilized willencompass other embodiments which may or may not be given therewith orelsewhere in the specification and all such embodiments are intended tobe included within the scope of that term or terms. Language designatingsuch nonlimiting examples and illustrations includes, but is not limitedto: “for example,” “for instance,” “e.g.,” “in one embodiment.”

Reference throughout this specification to “one embodiment,” “anembodiment,” or “a specific embodiment” or similar terminology meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodimentand may not necessarily be present in all embodiments. Thus, respectiveappearances of the phrases “in one embodiment,” “in an embodiment,” or“in a specific embodiment” or similar terminology in various placesthroughout this specification are not necessarily referring to the sameembodiment. Furthermore, the particular features, structures, orcharacteristics of any particular embodiment may be combined in anysuitable manner with one or more other embodiments. It is to beunderstood that other variations and modifications of the embodimentsdescribed and illustrated herein are possible in light of the teachingsherein and are to be considered as part of the spirit and scope of theinvention.

Although the invention has been described with respect to specificembodiments thereof, these embodiments are merely illustrative, and notrestrictive of the invention. The description herein of illustratedembodiments of the invention is not intended to be exhaustive or tolimit the invention to the precise forms disclosed herein (and inparticular, the inclusion of any particular embodiment, feature orfunction is not intended to limit the scope of the invention to suchembodiment, feature or function). Rather, the description is intended todescribe illustrative embodiments, features and functions in order toprovide a person of ordinary skill in the art context to understand theinvention without limiting the invention to any particularly describedembodiment, feature or function. While specific embodiments of, andexamples for, the invention are described herein for illustrativepurposes only, various equivalent modifications are possible within thespirit and scope of the invention, as those skilled in the relevant artwill recognize and appreciate. As indicated, these modifications may bemade to the invention in light of the foregoing description ofillustrated embodiments of the invention and are to be included withinthe spirit and scope of the invention. Thus, while the invention hasbeen described herein with reference to particular embodiments thereof,a latitude of modification, various changes and substitutions areintended in the foregoing disclosures, and it will be appreciated thatin some instances some features of embodiments of the invention will beemployed without a corresponding use of other features without departingfrom the scope and spirit of the invention as set forth. Therefore, manymodifications may be made to adapt a particular situation or material tothe essential scope and spirit of the invention.

In the description herein, numerous specific details are provided, suchas examples of components and/or methods, to provide a thoroughunderstanding of embodiments of the invention. One skilled in therelevant art will recognize, however, that an embodiment may be able tobe practiced without one or more of the specific details, or with otherapparatus, systems, assemblies, methods, components, materials, parts,and/or the like. In other instances, well-known structures, components,systems, materials, or operations are not specifically shown ordescribed in detail to avoid obscuring aspects of embodiments of theinvention. While the invention may be illustrated by using a particularembodiment, this is not and does not limit the invention to anyparticular embodiment and a person of ordinary skill in the art willrecognize that additional embodiments are readily understandable and area part of this invention.

Although the steps, operations, or computations may be presented in aspecific order, this order may be changed in different embodiments. Insome embodiments, to the extent multiple steps are shown as sequentialin this specification, some combination of such steps in alternativeembodiments may be performed at the same time. The sequence ofoperations described herein can be interrupted, suspended, or otherwisecontrolled by another process.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.Additionally, any signal arrows in the drawings/figures should beconsidered only as exemplary, and not limiting, unless otherwisespecifically noted.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any component(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or component.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention. Accordingly, thespecification, including the Summary and Abstract, and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

What is claimed is:
 1. A method for identifying an edge of a graphassociated with selected demographic data from a user database, themethod comprising: defining the graph within a bounded polygon, thegraph including a plurality of nodes and a plurality of connectionsbetween the nodes; receiving global positioning system (GPS) data pointsfor a plurality of GPS tracks from a plurality of GPS-enabled devices;mapping the GPS data points for each of the plurality of the GPS tracksto the graph by determining an activity track based on the GPS track,the activity track including a plurality of nodes from the graph and atleast one connection between the nodes; creating a path matrix includinga plurality of values, each value in the path matrix associated with (i)one of the plurality of connections between nodes of the graph and (ii)one of the determined activity tracks; defining a user profile vectorbased at least in part on the selected demographic data in the userdatabase; multiplying the path matrix and the user profile vector toobtain a resulting vector; and determining at least one edge of thegraph associated with selected demographic based on the resultingvector.
 2. The method of claim 1 wherein the resulting vector includesproperties indicative of frequency of traversal of each of the pluralityof connections of the graph in association with the selected demographicdata.
 3. The method of claim 2 wherein each of the activity tracks isassociated with user profile data in the user database, and wherein theuser profile vector is defined based on the user profile data.
 4. Themethod of claim 3 wherein the user profile data includes user gender andtype of activity.
 5. The method of claim 1 wherein defining the graphwithin the bounded polygon includes forming a bounding box based atleast in part on a maximum and a minimum of a longitude and a latitudeof the GPS data points for at least one GPS track.
 6. The method ofclaim 1 wherein defining the graph within the bounded polygon includesdetermining a simplified GPS sequence and forming the bounded polygonbased on the simplified GPS sequence.
 7. The method of claim 1 whereinreceiving GPS data points for the plurality of GPS tracks occurs priorto defining the graph within the bounded polygon.
 8. A non-transitorycomputer readable medium containing instructions for identifying an edgeof a graph associated with selected demographic data from a userdatabase by: defining the graph within a bounded polygon, the graphincluding a plurality of nodes and a plurality of connections betweenthe nodes; receiving global positioning system (GPS) data points for aplurality of GPS tracks from a plurality of GPS-enabled devices; mappingthe GPS data points for each of the plurality of the GPS tracks to thegraph by determining an activity track based on the GPS track, theactivity track including a plurality of nodes from the graph and atleast one connection between the nodes; creating a path matrix includinga plurality of values, each value in the path matrix associated with (i)one of the plurality of connections between nodes of the graph and (ii)one of the determined activity tracks; defining a user profile vectorbased at least in part on the selected demographic data in the userdatabase; multiplying the path matrix and the user profile vector toobtain a resulting vector; and determining at least one edge of thegraph associated with selected demographic based on the resultingvector.
 9. The computer readable medium of claim 7 wherein the resultingvector includes properties indicative of frequency of traversal of eachof the plurality of connections of the graph in association with theselected demographic data.
 10. The computer readable medium of claim 8wherein each of the activity tracks is associated with user profile datain the user database, and wherein the user profile vector is definedbased on the user profile data.
 11. The computer readable medium ofclaim 9 wherein the user profile data includes user gender and type ofactivity.
 12. The computer readable medium of claim 7 wherein definingthe graph within the bounded polygon includes defining a bounding boxbased at least in part on a maximum and a minimum of a longitude and alatitude of the GPS data points for at least one GPS track.
 13. Thecomputer readable medium of claim 7 wherein receiving GPS data pointsfor the plurality of GPS tracks occurs prior to defining the graphwithin the bounded polygon.
 14. A method for determining propertiesassociated with a graph, the graph including a plurality of nodes and aplurality of connections between the nodes, the method comprising:receiving global positioning system (GPS) data points for a plurality ofGPS tracks associated with the graph; mapping the GPS data points foreach of the plurality of the GPS tracks to the graph by determining anactivity track based on the GPS track, the activity track including aplurality of nodes from the graph and at least one connection betweenthe nodes; and creating a path matrix including a plurality of values,each value in the path matrix associated with (i) one of the pluralityof connections between nodes of the graph and (ii) one of the determinedactivity tracks.
 15. The method of claim 14 further comprisingperforming a mathematical operation on the path matrix in order todetermine at least one property for the graph.
 16. The method of claim15 wherein performing a mathematical operation on the path matrixincludes multiplying the path matrix by a first vector to provide asecond vector, the second vector having properties indicative offrequency of traversal of the plurality of connections of the graph. 17.The method of claim 16 wherein each of the activity tracks is associatedwith profile data, and wherein the first vector is derived based on theprofile data.
 18. The method of claim 17 wherein the profile dataincludes user gender and type of activity.
 19. The method of claim 14wherein the at least one property associated with the graph isindicative of (i) a frequency of traversal of the plurality ofconnections of the graph for a selected demographic of users or (ii)activity tracks that utilized a particular connection between the nodesof the graph.
 20. The method of claim 14 wherein the graph is boundedwithin a bounding box that includes the plurality of nodes.